The present invention relates to aircraft connectors for ground electrical supplies. More particularly, the invention relates to an aircraft fixed connector (receptacle) and ground supply free connector (plug) used on commercial and military aircraft. With newer aircraft having higher capacity load, ground power supply and aircraft multiple socket hook-ups are insufficient and inefficient.
When a commercial aircraft is docked at the airport and it""s self generating electrical power is shut off, the aircraft is plugged into the airport ground power system. Stated differently, a ground power cart can be connected to the airport power supply system with its ground supply free connector attached to the aircraft fixed connector which is usually mounted and located at the bottom of the exterior forward nose cargo area of the aircraft. Prior art aircraft power connector coupling is basically maintained through the physical engagement between the electrical contact pins on the aircraft""s fixed connector and the electrical contact sockets on the ground supply""s free connector. This coupling interconnection between the aircraft power receptacle and ground power plug is the major cause of failure. The heavy weight of the ground power plug pulling down on the electrical engagement between the pin and socket contacts may cause arcing when power is on. This condition coupled to the frequency of coupling and uncoupling on these connectors will result in eventual electrical breakdown. Other contributors to aircraft power connectors failures are: a) a damaged or worn receptacles or plugs can cause damage to aircraft and ground power units; b) the ground power plug could well be connected to several hundred aircraft receptacles during its life; c) no inspection of either aircraft receptacle or ground power plug before usage; d) no action and/or process to identify aircraft receptacle or ground power plug which may have damaged other aircraft power connectors; e) the environment in which the connectors are used cannot be controlled; f) the aircraft power connectors require considerable force to couple, resulting in incomplete coupling, particularly where this requires lifting the ground power plug above shoulder height; g) the staff or crew connecting the aircraft power connectors may have no electrical knowledge; and h) the standards to which the aircraft power connectors are maintained throughout the world can vary significantly. Replacement of either the aircraft fixed connector and/or ground supply free connector is a significant revenue loss to the airlines and airport.
The present invention in an illustrative embodiment describes 120 KVA aircraft power connectors using a hermaphroditic high amperage power contract, e.g., as shown in U.S. Pat. No. 5,174,777 to Carter, issued Dec. 29, 1992. The present embodiment supplies the electrical ground power needs on the newer, larger and higher capacity load aircraft. Furthermore, the hereinafter described aircraft power connectors ensure full electrical coupling and are self-attaching, which facilitates assembly of ground supply free connectors onto aircraft fixed connectors.
It is an object of this invention to overcome the herein above described deficiencies and disadvantages of the prior art.
It is another object of this invention to provide a new aircraft fixed connector (receptacle) and ground supply free connector (plug) which are: a) capable of providing a 120 KVA ground power supply with a reliable high electrical bearing interface; b) electrically and mechanically engaged when coupled; c) robust in construction; d) capable of withstanding heavy mechanical shocks and hard wear in use; and e) equipped with a positive coupling arrangement which will release automatically with a simple pull on a wire lanyard without damage to the aircraft fixed connector or its mounting.
A further object of this invention is to provide aircraft power connectors which comprise four hermaphroditic high amperage power contacts and two conventional relay contacts and receptacle and plug housing and its components wherein the aircraft fixed connector contains an integral mounting flange with four specially placed panel mounting holes. Also, this integral mounting flange contains another strategically placed hole with provisions for a slide latch fastener. A wire lanyard is attached to the slide latch fastener for releasing the latching pin on the ground supply free connector. The housing proximal end has an extended shroud designed to protect the mating ends of the electrical contacts and is constructed with a keyway. Additionally, boss like creepage barrier tubes independently surround each of the four hermaphroditic high amperage power contacts. Furthermore, attached to the electrical contacts but dielectrically insulated from each other are wire terminal studs with nut, washer and lockwasher.
The ground supply free connectors has an extended male boss which surrounds and protects the mating ends of the electrical contacts and has provisions for accepting the boss like creepage barrier tubes surrounding the hermaphroditic high amperage power contacts contained in the fixed connector. This extended male boss which forms part of the ground supply free connector has a matching key which is intended to allow one way assembly between the ground supply free connector and the aircraft fixed connector. This facilitates and eases the considerable force and sometimes blind mate condition when coupling the ground supply free connector onto the fixed connector. An environmentally sealing cable clamp or backshell having a male engagement thread is coupled onto the female thread provided at the distal end of the connector housing. Additionally, a reinforcing integral boss is strategically placed on the housing which accepts an extended but fixed latch pin. A wire lanyard is attached to the sliding latch that is part of the aircraft fixed connector that accepts the latch pin of the ground supply free connector. It can be seen that the mated integrity of the aircraft power connectors is maintained by the latch pin being captivated by the sliding latch. When it becomes necessary to unplug the ground supply free connector, a simple pull on the wire lanyard opens the sliding latch and the aircraft power connectors can be separated. It can also be seen that ground personnel on occasion may forget to disconnect the ground supply free connector as the aircraft begins its taxi to the runway, causing major damage to the ground power cart. The present invention has built-in contingency for releasing the ground supply free connector to the ground when the wire lanyard becomes taut. Another advantage of the present invention is that, realizing the physical abuse and environmental conditions that are normally inherent when using the ground supply free connector, a metal protective cover can be installed to lengthen its durability and life usage. This feature contains a set of plug face covers and trap like doors that open. The doors fully open prior to engagement on the electrical contacts of the aircraft power connectors.
A still further object of the present invention is to provide a ground supply free connector having an environmental protective cover which automatically open when being coupled to the aircraft fixed connector and closes when decoupled.
It is also an object of this invention to provide aircraft power connectors with replaceable contacts (when damaged or worn out) such that the ground supply free connector cable can be reused or aircraft fixed connector repaired thereby saving labor and time.
One embodiment of the present invention is the receptacle connector housing having an extended shroud with boss like creepage barrier tubes and keyway to engage an envelope of plug connector housing having male boss and key. Specifically, boss like creepage barrier tubes and male boss are constructed to protect the high amperage power contacts. Another embodiment is the full mechanical coupling between the aircraft fixed receptacle connector and ground supply free plug connector as provided by having the latch pin in the plug connector in a locked position within the receptacle connector slide latch fastener. These embodiments ensure full electrical contact engagement, user friendly assembly between plug and receptacle connectors, and eliminate prior art short life cycle on the high amperage power contacts. A wire release lanyard is provided in the slide latch fastener to decouple the external power connectors. Additionally, a metal housing comprising a set of doors attached to a set of hinge springs which are connected to a slide link protects ground supply free plug connector from adverse usage and extreme weather conditions. The set of doors is closed when the plug connector is at its uncoupled condition and is open when the plug connector is being coupled to the aircraft fixed receptacle connector. Movement on these doors is initiated by a spring-loaded actuator pin which is mounted in the face of the plug connector. An environmentally sealing backshell threadedly connected on the distal end of the ground supply free plug connector body or housing allows power and relay contacts to be replaced when necessary. Another embodiment of the present invention is the power and relay electrical contacts are replaceable. This property is non-existent in the prior art aircraft external power connector.